Many different types of implants for artificial joints are known in the prior art. Specifically, joint implants having a ball-and-socket type are used for hip and shoulder implants. However, implants of the ball-and-socket type may also be used in condyloid joints, such as the radiocarpal joint of the wrist, metacarpophalangeal joints of the hand and metatarsophalangeal joints of the foot.
In certain types of implants, notably the radiocarpal, metacarpophalangeal and metatarsophalangeal joints at least one degree of freedom of movement of a ball-and-socket joint has to be restricted such as to mimic the function of the natural joint. Further, in certain circumstances, it may also be beneficial to limit the degree of freedom of movement of a ball-and-socket joint in artificial hip or shoulder implants.
WO2010/105073 relates to a reverse shoulder assembly. In one example, a reverse shoulder assembly may be provided such that the reverse shoulder assembly alters the abduction force created by a patient's deltoid to a forward flexion force. In one example, a reverse shoulder assembly may be provided such that the reverse shoulder assembly alters the abduction force created by a patient's deltoid to an external rotation force. In one example, a reverse shoulder assembly may be provided such that the reverse shoulder assembly alters the abduction force created by a patient's deltoid to an external rotation force and a forward flexion force.